FR2952247A1 - MANAGING THE RECHARGE OF A BATTERY PARK - Google Patents

Abstract

A method for managing charging of at least one battery, characterized in that it comprises a transmission of a desired charge level (C) for a battery (i) at a given instant (T) so that charging allows the battery (i) to reach a charge level (C (i)) greater than or equal to the desired charge level (C) at the given instant.

Description

The invention relates to a method for managing the charging of at least one battery and a battery recharging device implementing such a method.

There are many battery operated devices, such as electric or hybrid vehicles. When the user of such an electrical device realizes that the charge of its battery is too low, it connects it to a recharging device which uses a source of electrical energy supplying a charging current of the battery.

When the electrical device concerned is an electric vehicle, the battery charging device may be in the form of a shelter defining a parking space and electrically equipped for the electrical connection with the battery. Such a shelter can be equipped with photovoltaic panels generating electrical energy which is used for recharging the vehicle's battery. In practice, the driver positions his vehicle under the shelter, electrically connects it to the energy source of the shelter to immediately initiate recharging of the battery. The recharging phase is then automatically stopped by the charging device as soon as the battery reaches its full charge.

Existing charging devices are not optimized. Indeed, the charging of the different batteries is initiated as soon as they are electrically connected, with the aim of being fully charged. However, this recharge may require energy from an expensive and / or polluting electricity source at the time of recharging the battery. In addition, this energy source may be insufficient at a given time, especially if several batteries are charging simultaneously and / or if renewable energy sources are used, such as a solar or wind source, by nature fluctuating. On the other hand, the total recharge of each battery may not be necessary for the intended future use.

Thus, there is a need for a method of intelligent management of the charging of one or more batteries of an electrical device.

A general object of the invention is therefore to propose an optimized management solution for recharging at least one battery of an electrical device, which achieves all or some of the following particular objects: A first object of the invention is to offer a solution for charging a battery at an optimized cost, with optimal energy efficiency.

A second object of the invention is to provide a charging solution 15 of a battery with minimal impact for the environment.

A third object of the invention is to provide a charging solution of a battery compatible with charging multiple batteries, a maximum of batteries simultaneously. To this end, the invention is based on a method for managing charging of at least one battery, characterized in that it comprises a transmission of a desired charge level (C ') for a battery (i). at a given instant (Ti) so that charging enables the battery (i) to reach a charge level (C (i)) greater than or equal to the desired charge level (C ') at the given instant .

The method for managing the charging of at least one battery can implement recharging of each battery (i) at a load (C (i)) substantially equal to the desired charge (C '), complying with the following condition : C 'CO) 1,1 C'.

The recharge management method may comprise a step of measuring the initial charge level (Co ') of a battery (i) and then a step of measuring its charge level during recharging.

The method for managing the charging of at least one battery can use several sources (j) of electric power generation for charging a battery and include minimizing the total cost for recharging the battery, minimizing the sum Ej 1 for Cost (j, t) S (j, t) dt, where Cost (j, t) represents the cost of a unit of energy produced by a source j at a time t and S (j, t) the amount of energy produced by a source j for recharging the battery at a time t, where J is the number of energy sources.

The method for managing the charging of at least one battery may include minimizing the environmental impact of recharging at least one battery, while minimizing the sum Ej 1 f Env Env (j, t) S (j, t) dt, where Env (j, t) represents the environmental impact of a unit of energy produced by a source j at a time t.

The method for managing the charging of at least one battery may comprise a minimization of the total energy Ej 1 fs (j, t) dt used for recharging at least one battery, and taking into account the maximum (Smax ') of energy available for each production source by the condition S (j, t) Smax1.

The method for managing the charging of at least one battery can take into account the recharge efficiency (r; (t)) of each battery at time t, defined by CO) = Co '+ f' (t) ) e (i, t) dt, where Co 'represents the initial charge level of the battery and e (i, t) represents the recharge energy supplied to each battery i at time t.

The invention also relates to a charging device for at least one battery comprising an electrical connection means with at least one battery, characterized in that it comprises a computer which implements the charging management method of at least one battery as described above.

The charging device for at least one battery may comprise a means of producing solar and / or wind energy. The charging device of at least one battery may comprise a communication means for transmitting a desired charge level (C ') for a battery (i) at a given instant (Ti).

These objects, features and advantages of the present invention will be set forth in detail in the following description of a particular embodiment made in a non-limitative manner with reference to the appended figures among which:

FIG. 1 diagrammatically represents the system implementing the battery charging method according to one embodiment of the invention.

FIG. 2 represents the evolution over time of the charge of two batteries and the energy produced by a recharging device according to an exemplary implementation of the invention. FIGS. 3a and 3b show the evolution in FIG. the time of the energies transmitted to the two batteries.

The invention will be illustrated in the case of a fleet of electric vehicles as an example. Such an electric vehicle can be an electric bike, an electric car, a segway, an electric scooter, etc. Naturally, the invention could be easily transposed to any electrical device equipped with a battery for its power supply, requiring recharging phases of its battery. In addition, for reasons of simplification, it will be considered in the following description that each vehicle is equipped with a single battery. However, the process could of course be applied similarly to vehicles with multiple batteries.

FIG. 1 thus schematically represents a system implementing the battery charging management method according to an embodiment of the invention, in which a battery recharging device 1, connected to one or more production sources, electrical energy S (j) through an electrical connection 2, comprises a battery charging means 11 of an electric vehicle 10.

The invention is based on the concept of taking into account the need to recharge the battery 11 of an electric vehicle 10. This need generally depends on the future envisaged and known use of the electric vehicle at the time of charging of its battery .

Thus, an essential step in the charging process of the battery of the electric vehicle 10 comprises the transmission of the recharging need by the user of the vehicle, or even by the vehicle itself in an automated manner according to route data previously entered by the driver, to the charging device 1. This need is expressed by the following two parameters: C represents the desired charge level of the battery, T represents the moment when the desired charge level C must be reached, or exceeded. Then, the recharging process as such of the battery naturally takes into account this need, so that at time T, the charge of the battery is at least equal to c, preferably substantially equal to or slightly greater than c, advantageously greater than 10% maximum this charge C. In the absence of the information of the load requirement, the method realizes the full charge of the battery by default.

The charge level represents the amount of electricity or energy available in the battery. This charge level will be determined at the initial time (Co to to) and then regularly, in real time or near real time during charging, by any known method of the state of the art, generally based on the measurement of electrical parameters such as voltage across the battery, temperature and current over time.

The charge level is therefore the parameter on which the charging method of the battery is based, in particular to determine the end of the charging by the detection of the desired charge C.

The measurement of the charge level of the battery is performed by a device integrated in the electric vehicle and associated with the battery. Alternatively, this measurement could be performed by the charging device

In addition, the model of the particular battery of a given electric vehicle is transmitted to the charging device, in particular to deduce the efficiency r of the charging process, which is defined as the ratio between the energy output of the battery on the recharge energy that had to be injected. This performance usually depends on the type of battery, and more precisely the technology used.

The battery recharging device therefore supplies a certain amount of recharge energy e to the battery 11, from a certain amount of higher energy u produced by one or more available energy sources S (j) and feeding the charging device. Finally, the recharge of the battery can be expressed by the following equations: C = Co + u u = re where C is the final charge level obtained and Co the initial charge level.

The charging method of the battery according to the embodiment of the invention takes into account that the electrical energy available at all times at the charging device is not infinite, depends on the various sources connected to the device of the invention. refill. This energy S (j) available for energy source load j is therefore increased by a maximum S max

The method of recharging the battery is based on the exploitation of J electric power generation sources j which produce electrical energy S (j) operated by the battery recharging device which transmits electrical energy e (i) to each battery i. This energy production S (j) induces a cost Cost (j) and an environmental impact Env (j) per unit of energy produced, which can be measured, including for example the release of CO2 into the atmosphere. All these parameters are variable over time. Finally, the method implemented by the invention can take into account the presence of several batteries i (in total I batteries) to be recharged, to a charge C 'desired at a given instant. Ti, from an initial charge Co '

The battery charging method therefore solves all or part of the following equations and conditions to deduce the charging conditions of each battery, from which power source and when:

At the moment Ti, the load C 'respects CO) C' z; _1 e (i) = zj 1 S (i) Minimize j fô `Cost (j, t) S (j, t) dt Minimize j fô` Env (j, t) S (j, t) dt 15 Minimize Ej 1 f S (j, t) dt With S (j, t) Smax j With CO) = r; e (i)

Condition (1) achieves the user's desired charge level for each battery and meets its requirement. Preferably, the final charge level CO) sought is substantially equal to the desired charge level C ', exceeding it by a maximum of 10%, and thus satisfying the following condition: C' CO) 1,1 C '. Equation (2) represents the energy balance of the system between the energy produced by the different sources of energy production and the energy consumed for recharging. Conditions (3) and (4) allow for recharging respectively at minimum cost and with minimal impact on the environment. Condition (5) allows charging to be performed at maximum energy efficiency. These last three conditions (3), (4), (5), favor recharging during periods when renewable energy sources (solar, wind ..) have a high electricity production. Condition (6) takes into account the maximum electrical output possible for each source. Equation (7) involves the yield r; recharge, which depends on the type of battery i considered. This performance of the battery is generally obtained experimentally. It is in general non-linear and the embodiment of the invention proposes a temporal discretization of the preceding equations and conditions and a logical transformation by binary variable in order to be able to write them in linear form despite the nonlinear nature of the yield r, and to facilitate the mathematical resolution of these equations, for example by a method of branch and bound.

The resolution of these conditions and equations makes it possible to obtain the energy S (j) to be produced and taken from each energy source j to charge each battery i. This solution also gives the distribution over time of these energies. By solving all or part of these conditions and equations, according to the desired complexity of the implementation of the invention, it is possible to ensure optimal anticipatory management of the battery recharge management. This solution represents a recharge plan, for a slippery horizon.

The invention also relates to a recharging device that implements the battery charging method as defined above. For this, the recharging device 1, shown schematically in FIG. 1, comprises a link 2 with one or more sources of electric power production S (j). In the illustrated example, it integrates photovoltaic panels 3 for local production of solar electric energy. It is also connected to the electrical network 4 whose electrical energy comes from different sources, such as wind or traditional sources 5 (gas, coal, nuclear ...). In such a case, the battery charging management method may include an estimate of the future production of solar electric energy, in particular from meteorological forecasts.

The recharging device 1 comprises an intelligence, in the form of any type of computer 7, allowing the implementation of the above method, and in particular the resolution of the mathematical equations mentioned, in order to determine the charging conditions of each connected battery 11. Finally, it comprises an electrical connection means 8 with a battery for the implementation of its charging and a communication means 9 for transmitting data with the vehicle and / or its driver as the battery charge level, the need of desired charge. This last parameter can be transmitted by the driver himself to the charging device via a man-machine interface or manually or automatically via the electric vehicle itself, for example from a calendar electronics, a telephone, an e-mail message, etc.

The invention thus makes it possible to achieve the desired objects and finally offers the following advantages: - as the recharging of the batteries takes into account the real need of each battery, it makes it possible to optimally manage over time the charging of the different batteries, most advantageous moment. In addition, it allows to recharge in parallel a maximum of batteries, since it does not necessarily seek the maximum and immediate recharge of all batteries connected to the charging device; the recharging over time of the battery also makes it possible to take into account the different configurations of the available sources of electrical energy, and to optimize the charges during advantageous moments, by using a maximum of energy sources at low cost and little polluting.

Figures 2, 3a and 3b illustrate the result obtained by a particular embodiment of the invention, wherein two electrical devices must be recharged at full load, the first for 13H and the second for 16H. Both electrical devices are connected to the charging device around 7am in the morning. The charging device is connected to the national electricity grid and includes photovoltaic panels with a capacity of 4 kW.

The curves 20 and 21 of FIG. 2 represent the variation in time of respectively the electrical production provided by the photovoltaic panels of the recharging device and the electrical production resulting from the electrical network. The curves 22 and 23 respectively illustrate the charges of the two batteries as a function of time. It is noted that during the entire period with significant sunshine, the electrical energy exploited comes mainly from photovoltaic panels. Power from the electricity grid is only used early in the morning. In addition, it appears that the management over time of the recharge makes it possible to meet the needs of both devices in terms of time. FIG. 3a comprises the curves 24, 25 which respectively represent the energy injected into the first battery and the energy actually accumulated in this battery as a function of time. It appears that this energy is strong and relatively constant from 7H to 13H. The difference between the two curves comes from the recharge performance of the battery, and represents the losses of the recharge, as has been explained before. Figure 3b similarly shows the curves 26, 27 which respectively represent the energy injected into the second battery and the energy actually accumulated in this battery, as a function of time. It appears that this energy is weak and relatively constant from 7H to 13H and strong between 13H and 16H. This distribution makes it possible to privilege at first the recharging of the first battery which must be ready earlier. It is noted that in the first hours when the two batteries are charging and where the sun is low, the charging device uses a certain minimum electrical energy from the electricity network.

Claims (10)

Revendications1. A method for managing the charging of at least one battery, characterized in that it comprises a transmission of a desired charge level (C ') for a battery (i) at a given instant (Ti) so that the recharging enables the battery (i) to reach a charge level (C (i)) greater than or equal to the desired charge level (C ') at the given instant. 2. A method of managing the charging of at least one battery according to the preceding claim, characterized in that it implements a recharge of each battery (i) to a load (C (i)) substantially equal to the load desired (C '), satisfying the following condition: C' CO) 1,1 C '. 3. Method for managing the charging of at least one battery according to one of the preceding claims, characterized in that it comprises a step of measuring the initial charge level (Co ') of a battery (i) then a step of measuring its charge level during charging. 4. A method of managing the charging of at least one battery according to one of the preceding claims, characterized in that it uses several sources (j) for producing electrical energy for recharging a battery and in that it includes a minimization of the total cost for charging the battery, minimizing the sum Ej 1 f `Cost (j, t) S (j, t) dt, where Cost (j, t) represents the cost of a unit of energy produced by a source j at a time t and S (j, t) the quantity of energy produced by a source j for charging the battery at a time t, where J is the number of sources of energy. 5. A method of managing the charging of at least one battery according to the preceding claim, characterized in that it comprises a minimization of the environmental impact of charging at least one battery, while minimizing the sum Ej 1 fô Where Env (j, t) represents the environmental impact of a unit of energy produced by a source j at a time t. 6. A method of managing the charging of at least one battery according to claim 4 or 5, characterized in that it comprises a minimization of the total energy Ej 1 fs S (j, t) dt used for recharging at least one battery, and taking into account the maximum (Smax1) of energy available for each production source by the condition S (j, t) Si max 7. A method of managing the charging of at least one battery according to one of the preceding claims, characterized in that it takes into account the recharge efficiency (r; (t)) of each battery at time t , defined by CO) = Co '+ f' (t) e (i, t) dt, where Co 'represents the initial charge level of the battery and e (i, t) represents the recharge energy supplied to each battery i at the instant t. 8. Device for recharging (1) at least one battery comprising an electrical connection means (8) with at least one battery, characterized in that it comprises a computer (7) which implements the method of managing the battery. recharging at least one battery according to one of the preceding claims. 9. Device for recharging at least one battery according to the preceding claim, characterized in that it comprises means for producing solar (3) and / or wind power. 10. Device for recharging at least one battery according to claim 8 or 9, characterized in that it comprises a communication means (9) for transmitting a desired charge level (C ') for a battery ( i) at a given instant (Ti).